The space station's toilet broke two weeks ago. The problem - confined to the urine side of the commode - forced the orbiting outpost's crew of an American astronaut and two Russian cosmonauts to flush manually with extra water several times a day.
Space shuttle Discovery brought up a new pump for the toilet, as well as the space station's newest room, a $1 billion Japanese lab.
Oleg Kononenko spent more than two hours installing the new 35-pound pump and hoses, then running three tests of the toilet while he talked with specialists at Russian Mission Control, located just outside of Moscow.
The toilet worked normally. It transports urine via air flow to the pump, which separates the gas and liquid.
"Let's start using it," Russian Mission Control told Kononenko, one of the two Russians living aboard the space station. "We'll keep our fingers crossed."
Kononenko was asked to give periodic reports on how the toilet was working.
While Kononenko fixed the toilet, other members of the shuttle and space station crews were busy making power, data, air and water connections on the newly installed lab, named Kibo, which means hope in Japanese.
Japanese astronaut Akihiko Hoshide installed the 37-foot lab on Tuesday, just as two crewmates were completing a spacewalk. He used the space station's robot arm to nudge the bus-sized lab into place.
On Wednesday, Hoshide "will get to turn the module on for the first time. That will be really exciting," said Emily Nelson, a space station flight director.
Later in the day, the 10 space fliers on the linked shuttle and station planned to open the doors to the lab and float in.
The long process of installing Kibo began with a spacewalk by Michael Fossum and Ronald Garan Jr. They removed covers and disconnected cables, then handed off to the robot arm-operators inside, who lifted the lab out of Discovery's payload bay and attached it to the space station.
The Japanese lab is bigger and more sophisticated than the two other labs at the space station. It sports a hatch to the outside and a robot arm for sliding out science experiments. A smaller arm will arrive next spring, along with an outdoor porch for holding the experiment packages.
The first part of Kibo - essentially a storage shed - was delivered by the last shuttle crew in March. The astronauts aboard the linked shuttle and station will attach the shed to the lab on Friday.
The lab work was just part of Tuesday's spacewalk, the first of three planned for Discovery's nine-day space station visit.
Fossum and Garan also helped remove a 50-foot shuttle inspection boom from the space station and get it back to Discovery. The boom, usually attached to the shuttle's robotic arm and used to conduct a detailed inspection of the spacecraft's wings and nose, was checked out Wednesday and its sensors appeared to be working properly.
The spacewalkers also worked on the station's jammed solar wing rotating joint. Fossum tried out some cleaning techniques on the joint, which is gummed up with metal shavings, while Garan put in a new bearing.
The joint has been used only sparingly since last fall, hampering energy production. The joint enables the space station's solar arrays, which provide electrical power, to rotate and track the sun. NASA still does not know where the grit came from or how best to deal with the problem.
The photos taken by the space station residents just before Monday's linkup uncovered just four small areas of tile damage on Discovery's belly. The damage is so slight that no detailed inspection will be required, said LeRoy Cain, chairman of the mission management team.